Quantum Fluctuation Theorems

Recent advances in experimental techniques allow one to measure and control systems at the level of single molecules and atoms. Here gaining information about fluctuating thermodynamic quantities is crucial for understanding nonequilibrium thermodynamic behavior of small systems. To achieve this aim, stochastic thermodynamics offers a theoretical framework, and nonequilibrium equalities such as Jarzynski equality and fluctuation theorems provide key information about the fluctuating thermodynamic quantities. We review the recent progress in quantum fluctuation theorems, including the studies of Maxwell's demon which plays a crucial role in connecting thermodynamics with information.Comment: As a chapter of: F. Binder, L. A. Correa, C. Gogolin, J. Anders, and G. Adesso (eds.), "Thermodynamics in the quantum regime - Fundamental Aspects and New Directions", (Springer International Publishing, 2018

From scalar to string confinement

We outline a connection between scalar quark confinement, a phenomenologically successful concept heretofore lacking fundamental justification, and QCD. Although scalar confinement does not follow from QCD, there is an interesting and close relationship between them. We develop a simple model intermediate between scalar confinement and the QCD string for illustrative purposes. Finally, we find the bound state masses of scalar, time-component vector, and string confinement analytically through semi-classical quantization.Comment: ReVTeX, 9 pages, 5 figure

Changes in the quality of life in patients undergoing orthognathic therapy : a systematic review

The aim of this study was to investigate the impact of orthognathic therapy on patients’ quality of life. Therefore, a systematic review was conducted including all prospective studies that compared pretherapeutic and posttherapeutic Oral Health Impact Profile (OHIP) or Overall Quality of Life (OQOL) questionnaire scores. Studies in patients with congenital deformities, clefts, or posttraumatic or cancer-associated deformities were excluded. Overall, 23 prospective studies were included; 8 used OHIP, 9 used OQOL and 6 used both questionnaires. A total of 1039 patients were identified (60.29% women, 39.71% men), with a mean age of 45.17 years. All analyzed studies showed in both OHIP and OQLQ an improvement of the quality of life in patients after orthognathic therapy. While improved scores could be observed in all investigated criteria, the studies demonstrated that social and aesthetic aspects showed the most prominent impact. Comparison of different Angle Classes showed, furthermore, that Class III patients had an even greater advantage over those with a Class II deformity. The review confirms that the quality of life in patients with orthognathic therapy improves significantly in all observed aspects. With regard to Angle Classes, Class III patients showed an even greater improvement than Class II patients

A Newly Developed Orthodontic-Logopedic Screening Procedure for Myofunctional Dysfunctions—A Pilot Study

Interdisciplinary, patient-specific cooperation between orthodontics and speech therapy plays an important role in the therapy of myofunctional dysfunctions. The following orthodontic-logopedic screening procedure is intended to objectify the diagnosis of such dysfunctions and the progress of therapy. A diagnostic questionnaire was prepared based on existing diagnostic questionnaires for myofunctional dysfunction. It contains 32 questions, with a clinical weighting of 0 to 50 points in total. This results in a point score. The lower the score is, the lower the need for therapy is. The study included 108 patients between the ages of 6 and 50 years. After screening, the patient population was divided into Group 0 (score < 15; no speech therapy need; n = 36) and Group 1 (score ≥ 15; a speech therapy need; n = 72). Group 1 was additionally randomized into Subgroups A (with speech therapy; n = 36) and B (without speech therapy; n = 36). After a treatment interval of 6 months, all patients in Group 1 were examined again with the help of the screening procedure. Statistical analysis (SPSS) and significance testing (Mann–Whitney U test) were performed. At baseline, there was no significant difference between patients in Subgroups A and B ( p = 0.157). Subgroup A had a median score of 25, and Subgroup B had a median score of 30. However, after the treatment interval, a significant improvement ( p = 0.001) for Subgroup A with a median score of 11 (mean score difference = 14.67) over Subgroup B with a median score 23 (mean score difference of 7.08) was observed. The developed screening procedure was shown to be equally applicable to all patients and treatment providers. With the help of the scores in point form, the need for speech therapy and the progress of such therapy can be objectified

GDF15 Promotes the Osteogenic Cell Fate of Periodontal Ligament Fibroblasts, thus Affecting Their Mechanobiological Response

Periodontal ligament fibroblasts (PdLFs) exert important functions in oral tissue and bone remodeling following mechanical forces, which are specifically applied during orthodontic tooth movement (OTM). Located between the teeth and the alveolar bone, mechanical stress activates the mechanomodulatory functions of PdLFs including regulating local inflammation and activating further bone-remodeling cells. Previous studies suggested growth differentiation factor 15 (GDF15) as an important pro-inflammatory regulator during the PdLF mechanoresponse. GDF15 exerts its effects through both intracrine signaling and receptor binding, possibly even in an autocrine manner. The extent to which PdLFs are susceptible to extracellular GDF15 has not yet been investigated. Thus, our study aims to examine the influence of GDF15 exposure on the cellular properties of PdLFs and their mechanoresponse, which seems particularly relevant regarding disease- and aging-associated elevated GDF15 serum levels. Therefore, in addition to investigating potential GDF15 receptors, we analyzed its impact on the proliferation, survival, senescence, and differentiation of human PdLFs, demonstrating a pro-osteogenic effect upon long-term stimulation. Furthermore, we observed altered force-related inflammation and impaired osteoclast differentiation. Overall, our data suggest a major impact of extracellular GDF15 on PdLF differentiation and their mechanoresponse

Frequency of Dental X-ray Diagnostics in Children and Adolescents: What Is the Radiation Exposure?

Children are exposed to ionizing radiation through radiographs during their development for various reasons. At present, there are no officially valid reference values for dental X-rays in children and adolescents for dental X-ray diagnostics. This study retrospectively examined 9680 extraoral dental radiographs in pediatric patients between 2002 and 2020. The aim was to analyze the radiation doses in pediatric patients, which indications were used, and whether there were specific age and gender differences. The evaluation showed that radiation doses were considered low, with dose area products of 2.2 cGy × cm 2 for a lateral cephalogram, 14 cGy × cm 2 for an orthopantomogram (OPG), and 45 cGy × cm 2 for cone beam computer tomography (CBCT). This corresponds to an effective dose of 1.5 μSv for a lateral cephalogram, 7 μSv for an OPG, and 33.8 μSv for CBCT. Of the 9680 images, 78% were orthopantomograms, and only 0.4% were CBCT images. OPG has become more important over the years, as reflected in the indication. Approximately one-third of all extraoral exposures are orthodontic indications. Overall, the indications were similar for both genders. According to the dental indications, boys were X-rayed slightly more frequently than girls (54.5–45.5%). A future publication of dose guide values and corresponding guidelines is of high priority

Bidirectional substance P signaling between periodontal ligament fibroblasts and sensory neurons under mechanical stress

IntroductionOrthodontic tooth movement (OTM) and treatment-associated pain are closely related processes driven by a local inflammatory response modulated by periodontal ligament fibroblasts (PdLFs). Increased levels of substance P (SP), a well-characterized tachykinin, has been demonstrated in the PdL following the application of orthodontic forces. Although traditionally considered as neurotransmitter modulating inflammatory processes and pain, recent evidence suggests that also non-neuronal cells contribute to SP signaling during OTM. Since sensory neurons also express the corresponding receptor NK1R, activation by SP appears to be possible. However, the contribution of PdLFs to SP signaling upon mechanical stress and their subsequent interaction with sensory neurons remain largely unexplored. Thus, the aim of the study was to investigate a potential SP-mediated interactions between PdLFs and sensory neurons advancing our understanding of molecular mechanisms underlying orthodontic pain during OTM.MethodsTAC1 and SP levels were quantified via qRT-PCR, Western blot, and ELISA in compressed human PdLFs. Their conditioned medium was applied to sensory-like SH-SY5Y neurons and their activation was assessed by morphological features, cFOS expression, and calcium influx. Conversely, PdLFs were stimulated with conditioned medium from capsaicin-activated SH-SY5Y neurons. Subsequently, cytokine expression, RANKL/OPG ratio and activation of immune cells and osteoclasts by PdLFs were evaluated.ResultsCompressive force induced a time- and intensity-dependent increase in TAC1 expression and SP secretion by compressed PdLFs with a peak at 24 h. Stressed PdLFs significantly increased neurite complexity, cFOS levels and calcium influx in sensory neurons, indicating their activation. Conversely, activated neurons elicited a robust pro-inflammatory response in PdLFs along with an increased osteoclastogenesis.DiscussionOur findings demonstrate that PdL fibroblasts could function as a novel non-neuronal source of SP modulating sensory neuron activation. Conversely, fibroblasts were also stimulated by SP effecting inflammation and osteoclastogenesis. These findings underscore a dynamic role of PdLF- and sensory neuron-derived SP that likely contributes to both pain perception and inflammatory bone remodeling during OTM